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Causes of River Bank Erosion in Bangladesh

Causes of River Bank Erosion of Bangladesh

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Causes of River Bank Erosion in Bangladesh

  1. 1. Causes of River Bank Erosion in Bangladesh:  Geological Shape: The flat delta lands of Bangladesh offer little resistance to the hydraulic forces of its rivers, particularly during periods of high flow. As a consequence, in many regions rivers such as the Jamuna run wide rather than deep: easily 10 km wide at places during high water, yet rarely in channels with sides deeper than two or three meters.  Mature stage of River: When rivers enter the mature stage (as in the case with the three mighty rivers, ganges, brahmaputra and meghna) they become sluggish and meander or braid. These oscillations cause massive riverbank erosion.  Sedmientaion in the River beds: The catchment area of the major rivers is about 1.65 million square km of which only 7.5 percent lies within the border of Bangladesh that generates 1200 km3 of run- off annually, only 10 percent of which is generated within Bangladesh. In addition to vast quantities of water, these rivers carry about 1.1 billion tons of sediment every year and are responsible for the prevalence of flooding and riverbank erosion in Bangladesh. Vulnerable Rivers: According to Banglapedia, The following rivers are vulnerable for bank erosion.  Jamuna  Ganga  Padma  Brahmaputra Factors that Accelerate Erosion:  Stream bed lowering or in fill  Flooding of bank soils followed by rapid drops in flow  Saturation of banks from off-stream source  Redirection and acceleration of flow within the channel  Poor Soil Drainage
  2. 2.  Wave Action  Excessive Sand/Gravel Extraction  Intense Water from Rainfall Impacts of River Bank Erosion:  Social Impact (Homelessness, Migration, Identity Crisis)  Economic Impact (Loss of Productive Land, Loss of Employment, Risk of Poverty)  Other Impact (Health Damage, Criminal Activities, Building Collapse) River Bank Erosion Losses in Bangladesh:  It is estimated that about 5% of the total FLOODPLAIN of Bangladesh is directly affected by erosion.  Bank erosion is taking place in about 94 out of 489 upazilas of the country.  At present, bank erosion and FLOOD hazards in nearly 100 upazilas have become almost a regular feature. Of these, 35 are severely affected.  Building sloping down due to river bank erosion.